Seam for woven wire belts and method of making the same



Jan. .28, i947. b. c. DILLEY EI'AL 2,414,935

SEAN FOR WOVEN WIRE BELTS AND METHOD OF MAKING THE SAME Filed March 1, 1943 A 3 3 10 5 A 3 37A Patented Jan. 28, 1947 SEAM FOR WOVEN WIRE BELTS AND IVIETHOD OF MAKING THE SAME Donald C. Dilley, Cleveland, and Robert R. Mc-

' Gregor, South Euclid, Ohio, assignors to The Lindsay Wire Weaving Company, Cleveland, Ohio, a corporation of Ohio Application March 1, 1943, Serial No. 477,574

' 2 Claims (01. 245-40) This invention relates to the manufacture of wire cloth belts for the productionof paper in a Fourdrinier machineor to'be used as a covering for cylinders employed in paper production. In either case a Wire cloth web must be joined at its ends by a seam to make an endless belt or covering. Our inventionis concerned with the seam and the methodof making it.

The conventional method of joining the ends of wire webs to make-endless belts for many years comprised sewingthe ends together with a wire strand looped back and forth around successive end portions across the web. More recently the ends of the Warp wires have been secured by soldering,brazingor welding. In either =case,-however, the seam has-been the portion of the belt to give the most trouble.

Rigid joints produced by soldering,brazing or welding, have resulted in stressing that portion of the belt beyond the elastic limit, as it bends. back and forth in use in a Fourdrinier machine. On the other hand, the production of seam joints by the usual stitching with a wire has several drawbacks. Thu if the stitching is sufiiciently reinforced to form an effective seam, it retards considerably the ability of the wire cloth in the immediate area to conform itself to the supporting and driving rolls of the Fourdrinier machine, and the result of such stiffening of the belt is a premature failure at or near the joint.

A second objection to the stitched joint results from the fact that in the normal sewing operation, conventionally performed .by hand, the operator pulls the single strand of stitch wire forcibly through the mesh openings, causing the stitch wire to bend sharply around the warp or weft wires. This sharp bending causes work hardening of the stitching wire. This not only contributes to the stiffening of the belt at the joint but renders the stitch wire itself brittle so that such wires frequently break.

In the ordinary wide belts it is not feasible to use a single length of stitch wire, and draw it successively through one end portion after another of the fabric, and therefore several short lengths have been employed and the loose ends of each length soldered or otherwise secured to the wire cloth. Ihis presents a further factor tending to stiffen the joint.

It is the object of this invention to overcome a the above-mentioned difficulties in forming a seam for a Wire cloth belt. To accomplish this we employ a stitch wire which is composed of a stitch wire comprising a single strand. This composite strand is conveniently referred to as a cable, and twisting and braiding operations are included in the general term cabling.

The composite strand is of comparatively short length to enable it to be readily passed through successive openings along the ends of the lengths to be joined. The second part of our novel treatment consistsof butt-joining a successive section of such stitching cable to the preceding section as the formation of the seam continues. Such butt-joiningmay be eifected by. welding or silver soldering. By this means we avoid the necessity of securing each-fastener wiredirectly to the fabric itself and thereby avoidthe stiffeningof the seam which has resulted in the' past.

The fact that the stitch wire is not a single filament but a group of twisted or braided smaller filaments presentsseveral advantages in the production of thejoint. Throughthe use of small diameterwires grouped into a cable of a size commensurate with a single. strand of wire as formerly employed the strength of the joint may be greately increased. Our composite strand of small individual strands is likewise much more flexible than the unit strand of corresponding strength.

As an illustration, it may be noted that it is customary in certain joints to utilize a wire of 0.020 inch in diameter. Such wire is roughly equivalent in the cross sectional area to a twisted composite of five wires each 0.009 inch in di ameter, or seven wires of 0.0076 inch in diameter. Y

Assuming that the materials of the unit filament and the composite strand are identical, nevertheless the bending stresses in the small individual strands are somuch less than in the large single wire that decidedly increased strength results.

We may, however, safely use in our composite strand, wires of higher tensile strength, though of lower flexibility, than would be permitted in the case of the single strand, and with such a cable the sizes of the individual wires may be so small that their aggregate cross-section is materially less than that of a permissible single wire and still the cable is superior in strength as well as flexibility to the single strand.

We may make our cable of stainless steel wires and produce a cable smaller than the single conventional phosphor bronze wire. Such cabled stitch wire may readily be small enough to cocupy freely the distance between adjacent Warp wires of the mesh. This avoids abrasive wear on the stitch wire by the warp wires and lengths the life of the belt.

In practice, the operator stitches the seam with our cabled stitch wire using such length as may be most convenient for the job. When enough of the wire length has been applied so that the remainder ceases to be convenient for operation, another length of cabled stitch wire is buttwelded or soldered to the length already formed into the seam. The exact point of union between the two lengths of the cable is, of course, a solid mass of material, but the area is small enough so that it has been found to constitute no interference in the stitching operation or in the ultimate flexibility of the seam.

Our invention is illustrated in the drawing hereof, in which Fig. 1 is a plan; Fig. 2 an edge V warp wires welded together ata to form a loop passing around the final weft wires of the two ends of the fabric and between adjacent warp wires which pass around such final weft wires. However, we do not intend to confine ourselves to any particular weave or to any particular stitch pattern, as various patterns may be employed with our composite stitch wire.

In Figs. 1 and 2, I0 indicates our composite stitch wire, which is shown as composed of a number of individual strands l I twisted together to make the small cable. At II! in Fig. l we have indicated the butt-weld between the first length of stitch wire and a second length designated lfla. In making the'seam the first wire [0, having its end soldered to the edge of the web, is passed by hand and drawn tightly through the successive mesh spaces between adjacent warp wires for several loops, and then the next strand wire Illa is butted against the extreme end of the strand l0 and the joint l2 formed by welding or silver soldering. After that the sewing continues until near the end of the strand lOa when a subsequent length is attached. This process of alternate stitching and butt-joining is continued until the seam extends across the width of the fabric, when the final length of stitching cable is joined to that edge of the web, as indicated at I Db in Fig. 3.

The sewing operation with our cable, by reason of its greater flexibility, may be performed in less time than with the single wire, while the buttjoining need require no more time than the previous method of soldering the end of the stitch wire to the web. The increased flexibility also enables a smoother joint to be readily produced. These advantages are additional to the very important increased life of our seam in use, as heretofore set out.

We claim:

1. The method of sewing together woven wire fabric plies comprising attachin to one edge of one ply a composite stitching wire composed of a plurality of individual wires cabled together, sewing such stitching wire back and forth through the adjacent ends of fabric plies to be joined until such length of wire has been nearly used, then butt-welding to the end of such length a similar composite strand and continuing the sewing with that strand until it is nearly used in the seam, continuing such seaming and welding alternately until the opposite edge of the fabric is reached, and attaching the final length of stitching cable to that edge of the fabric.

2. A woven wire fabric, the ends of which are joined by a seam comprising a cable of small wires passing alternately through mesh openings in the opposed lengths of th fabric, the endmost portion of the stitching cable being attached to the edge of'the web.

DONALD C. DILLEY. ROBERT R. MCGREGOR. 

